In a plant comprising a plurality of parallel groups of gas cleaners, it is important that the connections to a common manifold which receives the purified gas are so designed that the pressure conditions at the connections are equal. In prior art designs this has not been the case. The flow in the parallel-working cleaners has become different. Therefore, it has not been possible to attain an optimum cleaning efficiency. In a PFBC power plant in which cleaners are located in an expensive pressure vessel and the gas is utilized for operation of turbines, it is particularly important for the cleaning plant to operate with optimum efficiency so that the size can be limited while maintaining a good dust separation and a small dust load in the propellent gases of the turbine.